.totail{width: 100%;background: #a9a9a9;height: 700px;}
.top{width: 100%;height: 100px;}
.top span{display:block; text-align: center;line-height: 100px;}
.middle{width: 100%;height: 500px;}
.middle-l{width: 50%;height: 100%;background: blue;float: left;}
.middle-r{width: 50%;height: 100%;background: green;float: right;}
.middle span{display:block; text-align: center;line-height: 500px;}
.footer{width: 100%;height: 100px;}
.footer span{display:block; text-align: center;line-height: 100px;}
